Cooling of electronics components can be achieved by impinging gas or liquid onto such components via gas jets, or mixed liquid/gas flows (i.e., liquid sprays in a surrounding gas phase). FIG. 1 is a schematic diagram that depicts a conventional cooling jet system for cooling electronic components, referenced collectively as the electronics system 10.
The electronics system 10 includes a plurality of electrical contacts 12 connecting a chip carrier circuit board 14 onto which electronic components may be fixed. An exemplary electronic chip 16 has its own set of electrical contacts 18 that plug into or are connected to the circuit board 14. A chip cap 20 may be provided to cover the circuit board 14 and the connected electronic chip 16, so as to isolate the chip to prevent contamination by outside dust, moisture, and other contaminants that may operate to undermine chip performance.
It will be appreciated that in operation, the electronic chip 16 generates a degree of heat, which if not dissipated can result in damage to, or even destruction of, the electronic chip and any other surrounding electronic components. Accordingly, a cooling system is provided. In the conventional configuration of FIG. 1, the cooling system includes an inlet 22 for providing a supply of cooling fluid, which may include a cooling liquid (e.g., water), a cooling gas (e.g., air), or a combined suitable liquid/gas mixture. The cooling fluid travels under pressure through a first manifold 24 to a jet plate 26 that has a plurality of jets 28. The jets 28 administer the cooling fluid to the surface of the chip to remove the heat generated by the chip. The cooling fluid is maintained within the area adjacent the chip by seals 29. The cooling fluid, now having drawn the heat from the electronic chip, is discharged under pressure from the electronic chip 16, through a second manifold 30 and out of an outlet 32.
Recent developments in such impingement cooling have focused on optimizing geometric and flow parameters to maximize cooling efficiencies obtainable with the general concept of impingement cooling. In addition, combinations of jet impingement with other cooling techniques (such as evaporative or thermo-electric cooling using the Peltier effect) have been investigated to further enhance cooling efficiencies. There have been attempts, therefore to optimize cooling efficiency by timed activation of rows and/or columns of jets within the cooling jet array for the purpose of driving a bulk motion in the jet discharge volume between a jet nozzle wall and a cooling surface. Timed activation has proven deficient, however, as being insufficiently related to actual temperature conditions. Under a timed activation, cooling fluid is discharged against the electronic components even when actual temperature conditions do not warrant cooling.
As an alternative to the timed activation control referenced above, which is imprecise in relation to actual temperature conditions, conventional impingement cooling systems have operated under active control. Such active control gathers sensory input pertaining to temperatures in the vicinity of different sections of the jet cooling array in such a way that cooling jets are only deployed or activated at positions where temporary hot spots occur on the electronics board. In particular, active controlled systems may involve logical electric circuits using temperature measurement via temperature sensors, signal transmission, controller processing and subsequent signal generation, and activation of piezo-electric orifices to open and close individual cooling jets or groups of cooling jets within the array. Active control systems, however, by employing sophisticated sensors and related control electronics, have proven deficient due to their complexity and implications for manufacturing, operation and maintenance.